Circuit breaker



P 1933- R. c. DICKINSON 1,927,888

CIRCUIT BREAKER Filed Jan. 24, 1931 3 Sheets-Sheet l WITNESSES INVEIQTOFS M M Faberz aflzc/fmsorz MA BY 'ATTORNI sept- 1933- F. c. DICKINSON 1,927,888 1 CIRCUIT BREAKER Filed Jan. 24, 1931 3 Sheets-Sheet 5 o o 1-, o 0

A97 .53 I 67 0 Q 7 WITNESSES INVENTOR 3 P046677 Z1750" Patented Sept. 26, 1933 UNITED STATES PATENT OFFICE CIRCUIT BREAKER Application January 24, 1931. Serial No. 511,010

23 Claims.

My invention relates to circuit breakers and more particularly to devices for extinguishing high-voltage, large-current arcs in air or gas.

My invention is an improvement upon circuit interrupters of the type disclosed in Patent No. 1,784,760, issued December 9, 1930, to the as-- signee of this application; and other improvements in circuit interrupters oi this type are described and claimed in copending applications 0 Serial No. 510,981 filed January 24, 1931 by F. B. Johnson and Serial No. 511,184 filed January 26, 1931 by Joseph Slepian, both assigned to the assignee of this application.

In the circuit breaker disclosed in the above mentioned patent, an arc is drawn and moved into a deionizing structure under the action of a magnetic field. The deionizing structure comprises a plurality of spaced plates having V- shaped slots into which the arc is moved and split into a plurality of short arcs between the plates and rotated at a high velocity until the zero point on the alternating-current wave is reached, when the arcs are extinguished.

An object of my invention is to provide a deionizing structure of the type mentioned above in which the stack of plates is open at both the top and the bottom so that there is a direct vent for each short arc. This makes possible the use of a smaller blow-in field structure, since the building up of gas pressure ahead 01 the arc-is prevented. In addition to the fact that the gas pressure does not retard the movement of the are through the stack, the flow 01' gas aids in moving the are into the structure.

I The use 0! a stack'of deionizing plates open at the top and bottom also permits ventilation through the stack. This makes possible such movement of the ionized gases across the plates that they are effectively deionized. The contin- 40 uous flow 01' gas between the plates also increases the rate at which heat is conducted away from the plates. This allows the structure to be used for interrupting circuits carrying large currents and for interrupting the circuit a larger number of times in succession without overheating.

A further object of my invention is to provide an annular path for the arc defined by insulating spacers between the deionizing sheets with a ventilating passage at one side of the annular path around which the arc is rotated in such direction that the movement of the are at the vent is in the opposite direction to the flow of gases out of the vent. This renders it unlikely that the arc will be blown out of the ventilating passage by the moving gases.

A further object 01 my invention is to provide a pair of arc horns on which the arc is extended and moved into the deionizing structure and which has ventilating slots therein. This allows the free circulation of gas outwardly between the arc horns ahead of the arc when it is being moved upwardly thereon and up into the deionizing structure when the arc has been moved into the spaces between the plates.

A further object of my invention is to provide 6 a static shield for the deionizing plates which is open at the top so that the arc gases can flow therebetween.

A further object of my invention is to provide a pair of arc horns in which the direction of cur- 7 rent flow is such that the reaction between the magnetic fields set up by the current in the arc horns and the current in the arc is such as to move the arc upwardly on the arc horns.

These and other objects and advantages of my invention will be made apparent from the following description of a specific embodiment of the invention which is illustrated in the draw- 1 8s, in which Figure 1 is a diagrammatic view, partially in 50 section, through my circuit interrupter.

Fig. 2 is a sectional view through the circuit interrupter of Figure 1, on the section line 11-11.

Fig. 3 is a detail sectional view on line III-III 01' Fig. 2. 35

Figs. 4, 5 and 8 are side-elevational views of the deionizing plates embodied in the circuit interrupter.

Figs. 7 and 8 are side elevational views or the insulating spacers located between the plates shown in Figs. 4, 5 and 6.

Fig. 9 is a diagrammatic view showing the relations between the magnetic fields set up by the current flowing in the arc horns and the current in the are. 5

Referring to Fig. 1, the circuit breaker 11 comprises a pair of separable main contacts 13 and.

15 which are connected to the circuit to be interrupted by conductors 1'1 and 19. A pair of arcing contacts 21 and 23, 01 copper, are electrlcally connected in parallel with the main contacts l3 and 15. The contacts are opened by operating mechanism of any suitable type so that the main contacts 13 and 15 are first separated without drawing any appreciable arc, and the circuit is then completely opened by the separation of arcing contacts 21 and 23.

The arcing contact 23 is provided with a movable arc horn 25 of magnetic material so that, when the arc is drawn, it is transferred to a pair of fixed iron are horns 27 and 29. A blow-in magnet 31, having a pair of legs 33 extending along each side of the deionizing structure, is provided with a magnetizing coil 35, one end of which is electrically connected, through conductor 37, to conductor 1'7, and the other end of which is connected, through conductor 39, to the arc horn 27. The first section of the arc that is drawn jumps to the stationary arc horn 2'7, due to the attraction of the are by the iron, so that it is connected in shunt to the magnetizing coil 35. Since the voltage drop through the magnetizing circuit is less than that necessary to sustain the are between contact 21 and are horn 2'7, this are is extinguished, and the blow-in coil 35 is then inserted in series with the arc. The other end of the arc is transferred from the moving arc horn 25 to the other stationary arc horn 29. Both of the stationary arc horns 2'7 and 29 and moving arc horn 25 are constructed of magnetic material, such as iron, so that the arc will be attracted thereto because of the distortion of the magnetic field set up by the current flowing in the arc.

The are horns 2'7 and 29 have arc-terminal portions 41 and 43 on which the ends of the are are moved, and current-conducting portions 45 and 4'7 which are electrically connected to the inner ends of the arc-terminal portions. The outer ends of the current-conducting portions are insulated from the arc-terminal portions and electrically connected in the circuit. It will thus be seen that the direction of current fiow is that indicated by the arrows. With the current flowing from conductor 3'7, through the blow-in wind ing 35, conductor 39, along the current-conductor portion 45 and upwardly in the arc-terminal portion 41, the current then flows, through the arc, to the arc-terminal portion 43 of are born 29 and then downwardly and outwardly, through ourrent-carrying portion 47, to the line 19. This is illustrated diagrammatically in Fig. 9. As shown by the arrows, the current fiows upwardly on one are horn and downwardly on the other are horn. The magnetic fields set up by the currents in the arc horns are indicated by the arrows 49 and 51, while the direction of the magnetic field set up by the current in the arc is indicated by the arrows 53 and 55. The magnetic fields, due to the currents in the arc horns and in the arc, are in the same directions in the angular spaces between the arc and the arc horns. These opposing fields repel each other so that the arc is moved upwardly on the arc horns. This will also be seen if it is noted that the direction of current flow in each of the arc horns is in a direction opposite to the current flowing in the arc, so that there is a force of repulsion between them.

The deionizing structure comprises a plurality of groups of plates 5'7 separated by coil sections 59. Each of the deionizing sections 57 comprises a plurality of copper plates 61, shown in Fig. 4, which are spaced apart by insulating members 63 and 65, of sheet material, such as fish paper, which are shown in Fig. '7. The assembly of alternate sheets of insulating material and copper plates is shown in Figs. 2 and 3. Each of the copper plates 61 is provided with a downwardly extending portion 67 provided with a converging slot 69. A hole '71 is provided near the center of each sheet through which a through bolt may be passed. A narrow slot '73 is provided in each sheet from its edge to the hole '71. The plates 61 are so assembled in each group that alternate plates have the slots '73 on opposite sides, as shown in Fig. 2. The slots '73 are provided for the purpose of preventing the fiow of eddy-currents in the plates, thus reducing the magnetic losses.

The insulating sheets 63 and 65 are so shaped that, when placed together between the copper plates 61, they define an annular path '75 between the plates 61. The insulating sheet 65 has a projection '77 extending from one side thereof to form the top of the annular path. Projection 7'7 is of such length that a ventilating passage '79 is provided between the end thereof and the inner edge of insulating sheet 63. The ventilating passage '79 is outwardly fiared above the projection '77 to form a wide passage 81 in which the gases formed by the arc may expand and have a large area contact with the plates 61, so that they will be cooled and deionized before being emitted from the top of the stack. The insulating sheets 63 and 65 of each of the plates are provided with extensions 83 and 85 which form a narrow passage 87 along-the slots 69.

It is thus seen that there is a through path between the plates 61 from the lower passage 87, through the annular arc path '75 and ventilating passages '79 and 81. This allows a fiow of gas through the stack so that there is no pressure built up ahead of the arc to retard its movement which would require the use of a stronger magnetic field for moving the arc. This through fiow of gas also rapidly cools and deionizes the arc and provides for the rapid dis sipation of the heat from the deionizing plates 61.

Each of the arc horns 2'7 and 29 is formed of a plurality of spaced plates 89, providing ventilating passages 91 therebetween. The provi sion of ventilating passages 91 permits the movement of gas through the arc horns and up into the passages 87 between the plates so that the arc horns do not act to close the. bottom of the spaces between the plates, thus allowing free ventilation.

Each of the radial field coil sections 59 comprises a radial field coil 93 and a coil-end plate 9'7 on each side thereof electrically connected to the ends of the coil. Plates 9'7, shown in Fig. 5, are provided with a central opening 99 and a slot 101. Adjacent to the lower end of each coilend plate 9'7 is positioned a coil-end transfer plate 103 having a converging slot 105. Arctransfer plates 107 are placed beneath the coils 9'7 between the coil-end plates and are provided with slots 109. Transfer plates 107 are spaced apart by insulating spacers 111 provided with a passage 113 for the arc and having a circular opening 115 at the upper end thereof. The space above the coils 97 and between the coilend plates. 9'7 is filled with an insulating block 115.

The coil sections 59 are so placed between the groups of defonizing plates 57 that the direction of the radial field, set up by adjacent coils, is in opposite directions, as indicated by the arrows 117 in Fig. 1. This makes the direction of the magnetic field, due to the adjacent coils, in the same direction in the group of plates between the coils, while the radial fields in adjacent groups of plates are in opposite directions.

As the arc is moved up on the arc horns 2'7 and 29 by the infiuence of the blow-in field magnet 31 and the magnetic field set up by the current fiowing in the arc horns, the arc is moved into the slots 69 in the deionizing plates, slots 105 in the coil-end transfer plates and slots 109 in the transfer plates.

The are is thus so constricted in cross-section that it has a high current density when it reaches the tips of the slots. The arc is then split into a plurality of short cold-cathode arcs between the various plates. As the arc is farther moved upwardly, it jumps across the gaps 119 between the coil-end plates 97 and the coil-end transfer plates 103. The voltage drop through the radial field coils 93 is then less than that necessary to maintain the arcs between the transfer plates 107 so that these arcs are extinguished, and the coils 97 are inserted in series with the arcs playing between the groups of deionizing plates 57. The energization of coils 93 sets up a radial magnetic field between the plates which acts on the arcs to rotate them around the annular path 75. Since the radial fields are in opposite directions in adjacent groups of plates, as shown in Fig. 1, the rotation of the arcs will be in opposite directions in adjacent groups of plates.

The insulating plates 63 and 65 are so disposed that, if the arc rotates in the annular path in the direction indicated by arrow 121, the ventilating opening 79 will be so positioned on that side of the annular paththat the direction of the flow of gas out of the opening will be opposite to the movement of the are. This reduces the possibility of the are being blown out of the ventilating passage by the moving gas. Since the arcs rotate in opposite directions in adjacent groups 57, the plates 63 and 65 are reversed in adjacent groups, as shown in Fig. 2 by the broken lines.

The groups of plates 57 and coils 59 are secured together between end plates 123 and 125, electrically connected to the arc horns 27 and 29. A through bolt 127 in an insulating tube 129 is placed through the aligned openings 71 and 99 in the plates 61 and 97. Insulating rings 131 of fish paper are placed between each of the copper sheets 61 around the tube 129 of a fibrous material impregnated with a condensation resin to define the inner edge of the annular arc path 75. The lower portion of the assembled stack of plates and coils is supported and secured together by insulating rods 135 of wood impregnated with a condensation resin having metal end caps 133. Plates 137 of fibre are arranged along each side of the arc horns 27 and 29 and have sections of arc-resisting material 139, such as asbestos, inserted therein.

The magnetic field produced by the blow-in magnet 31 is provided with a path of low reluctance so distributed as to be most effective in moving the arc into the deionizing structure by the provision of laminations 141 of iron spaced apart by sheets of fish paper 142 positioned beside the passageway in which the arc is drawn. As shown in Fig. 1, the laminations 141 are of different lengths. The sections 143, adjacent to each of the arc horns, are of such length as to extend down to the arc horns. A longer secton 145 is provided beside the contacts 21 and 23 and main contacts 13 and 15 to move the arc drawn therebetween. The intermediate section 147 of the laminations 141 are of a length between those of section 143 and section 145 so as to extend beside the moving arc horn. The iron laminations 147 and an insulating sheet of fish paper 148 are clamped between the fibre plates 137 and wood blocks 142.

As shown in Fig. 2, a static shield is provided comprising plates 149 of insulating material having a layer 151 of conducting material, such as tinfoil, embedded therein. The static shield acts to equalize the difference in potential between copper plates 61 due to the capacity between the plates 61 and the sheet of metal foil 151. The use of spaced static shield members 149 which are open at the top allows the through flow of gas from the stack so that most effective deionizing action is obtained.

Each of the metal plates 61, 97 and 107 is provided with detents 153 pressed therein, while each of the insulating sheets 63, 65 and 115 is provided with holes 155 which are disposed to register with the detents 153 when the plates and insulating members are so assembled that the de tents fit into the holes and keep the insulating and conducting plates in proper alignment.

From the foregoing description, it is apparent that I have provided a most efficient deionizing structure having a large thermal capacity with means for dissipating heat at a rapid rate. This makes possible the interruption of arcs carrying heavy currents in rapid succession without overheating the deionizing structure.

While a specific embodiment of the invention has been shown and described which embodies numerous novel features, it should be understood that these features may be used separately and in various combinations and that numerous modifications may be made without departing from the spirit of the invention as set forth in the following claims.

I claim as my invention:

1. In an arc-extinguishing structure, a plurality of means of conducting material between portions of which the arc is split up into a plurality of short arcs, said means of conducting material providing annular paths for the arcs, ventilating passages extending from one edge of said means of conducting material to another edge thereof between the surfaces thereof and a plurality of sheets of insulating material between said means of conducting material and extending around the outer peripheries of said annular paths, said sheets of insulating material having portions extending transversely across the path of flow of gas in said ventilating passages for a large portion of the width of said annular paths.

2. In an arc-extinguishing structure, a plurality of means of conducting material between portions of which the arc is split up into a plurality of short arcs, said means of conducting material providing annular paths for the arcs, ventilating passages extending from one edge of said means of conducting material to another edge thereof between the surfaces thereof, said ventilating passages having a width at one edge of said means of conducting material equal at least to a large portion of the width of said annular paths, and a plurality of sheets of insulating material between said means of conducting material and extending around said annular paths for the major portion of the outer peripheries thereof.

3. In an arc-extinguishing structure, a plurality of means of conducting material between por tions of which the arc is split up into a plurality of short arcs, said means of conducting material providing annular paths for the arcs, ventilating passages extending from the bottom edge of said means of conducting material to the top edge thereof between the surfaces thereof, a plurality of sheets of insulating material between said means of conducting material and extending around the major portion of the outer peripheries of said annular paths, said sheets of insulating material providing narrow entrance passages into tween said means of conducting material and the gases which flow-through said ventilating passages.

4. In an arc-extinguishing structure, a plurality of means of conducting material between portions of which the arc is split up into a plurality of short arcs, said means of conducting material providing annular paths for the arcs, and a plurality of sheets of insulating material between said means of conducting material and extending around the major portion of the outer peripheries of said annular paths, saidsheets of insulating material leaving a large area of the surfaces of said means of conducting material uncovered outside of said annular path and permitting flow of gas from said annular paths across said surfaces.

5. In an arc-extinguishing structure, a plurality of conducting members, and a plurality of pairs of insulating members between said conducting members, said pairs of insulating members having wide spaces therebetween at one end and narrow spaces at the other end, and means rendering movement of the are out of said structure through said wide spaces unlikely.

6. In an arc-extinguishing structure, a plurality of conducting members, and a plurality of pairs of insulating members between said conducting members, said pairs of insulating members having wide spaces therebetween at one end, and one of said insulating members in each pair having a projection extending into said wide space to restrict movement of the arc therefrom.

7. In an arc-extinguishing structure, a plurality of sheets of conducting material between whichthe arc moves, a ventilating passage leading from said plates and so positioned that the flow of gas in said passage is in a direction opposite to the motion of the arc at said passage.

8. In an arc-extinguishing structure, a plurality of sheets of conducting material and insulating spacers therebetween to define a curved path, a vent leading from said path along a tangent, and means for moving the are along said curved path adjacent to said vent in a direction opposite to the flow of gas out of said vent.

9. In an arc-extinguishing structure, a plurality of groups of sheets of conducting material and insulating spacers therebetween to define an annular path for the arc and having ventilating passages leading therefrom at one side thereof, said ventilating passages being at opposite sides of said annular path in adjacent groups.

10. In an arc-extinguishing structure, a plurality of groups of deionizing members, means for rotating the arc in opposite directions in adjacent groups of said deionizing members, means for holding said deionizing members in spaced relation, said means having ventilating passages leading from the path of rotation on said are on opposite sides of said path in adjacent groups.

11. In an arc-extinguishing structure, a plurality of sheets of conducting material having converging slots therein, a plurality of sheets of insulating material between said sheets of conducting material and having narrow passages along said slots, widened portions in which the arc is rotated, and widened ventilating passages.

12. In an arc-extinguishing structure, a plurality of sheets of conducting material having convergingslots therein, a plurality of sheets of insulating material between said sheets of conducting material and having narrow passages along said slots, widened portions in which the arc is rotated, and widened ventilating passages connected to said passages in which the arc is rotated by narrowed passages which restrict movement of the arc out of the structure.

13. In a circuit interrupter, the combination with an arc horn having ventilating slots therein, of a plurality of sheets between which the are is moved and open spaces between said sheets extending from adjacent to said arc horn to one edge of said sheets.

14. In a circuit interrupter, the combination with an arc horn comprising metal plates having spaces therebetween, of a plurality of conducting sheets having through ventilating passages therebetween.

15. In a circuit interrupter, a pair of diverging arc horns having ventilating slots therein, and means for deionizing the arc comprising a plurality of conducting sheets and a plurality of insulating spacers between said sheets along opposite edges thereof and having a plurality of ventilating passages extending from a point adjacent to said are horns to the opposite sides of said sheets.

16. In a circuit interrupter, a pair of diverging arc horns having ventilating slots therein, and means for deionizing the arc comprising a plurality of conducting sheets having converging slots therein adjacent to said are horns and a plurality of insulating spacers between said sheets along opposite edges thereof and having a plurality of ventilating passages extending from a point adjacent to said are horns to the opposite sides of said sheets.

17. In a circuit interrupter, means for deionizing an arc comprising a plurality of spaced conducting members, and means for maintaining a predetermined potential balance between said conducting members comprising conducting sheets having a through ventilating passage therebetween.

18. In a circuit interrupter, means for deionizing an arc comprising a plurality of spaced conducting plates between which the arc is split into a plurality of short arcs, and means for causing a substantially uniform potential difference between said conducting plates after interruption of the arc comprising conducting sheets placed along opposite edges of said conducting plates. the spaces between the other edges of said sheets being open to permit ventilation.

19. In a circuit interrupter, means for deionizing an arc comprising a plurality of spaced conducting plates between which the arc is split into a plurality of short arcs, and means for causing a substantially uniform potential difference between said conducting plates after interruption of the arc comprising a pair of plates of insulating material having sheets of metal foil embedded therein and secured along opposite edges of said conducting plates, and ventilating passages between said conducting plates unobstructed by said plates of insulating material.

20. In an arc-extinguishing structure, a pinrality of sheets of conducting material spaced apart by sheets of insulating material, some of said sheets having indentations therein and others of said sheets having holes therein to register with said indentations for retaining said sheets in position.

21. In an arc extinguishing structure, a plurality of plates of conducting material having V-shaped slots therein, means for moving thearc into said V-shaped slots to split up the are into a plurality of short arcs between said conducting plates, means of insulating material positioned between and spacing apart some of said sheets of conducting material adjacent the outer edges of said structure, and a ventilating passage extending from between said plates to an outer edge of said structure at a point spaced from said V-shaped slot and said insulating means at the outer edges of said structure forming a barrier extending at least partially across said ventilating passage.

22. In an arc-extinguishing structure, a plurality of plates of conducting material between which the arc is split into a plurality of short arcs, said plates being spaced apart by a plurality of sheets of insulating material so shaped as to define an annular path for the arc and means providing a through ventilating passage between said plates of conducting material, and means in said ventilating passage for restricting movement of the are out of said ventilating passage between said plates of conducting material.

- 23. In an arc-extinguishing structure, a pluralityof plates of conducting material between which the arc is split into a plurality of short arcs, each pair of said plates being spaced apart by a plurality of sheets of insulating material some of which are so shaped as to define an annular path for the arc and means providing a through ventilating passage between said plates of conducting material, and means for restricting movement of the are out of said ventilating passage between said plates of conducting material, said means including a portion of each of said sheets of insulating material having such dimensions as to leave said ventilating passage for the escape of arc gases.

ROBERT C. DICKINSON.

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